Field
The disclosed concept pertains generally to electrical switching apparatus and, more particularly, to electromagnetic switching devices, such as, for example, power contactors. The disclosed concept further pertains to systems including such power contactors.
Background Information
Electromagnetic switching devices, such as power contactors, are often used to electrically couple a power source to a load such as, for example and without limitation, an electrical motor or other suitable load. An electromagnetic switching device can include both fixed and movable electrical contacts as well as an electromagnetic coil. Upon energization of the electromagnetic coil, a movable contact engages a number of fixed contacts so as to electrically couple the power source to the load. When the electromagnetic coil is de-energized, the movable contact disengages from the number of fixed contacts thereby disconnecting the load from the power source.
Power contactors can include a plurality of inputs for a plurality of power sources and a plurality of outputs for a plurality of loads. The outputs can include normally open (NO) and/or normally closed (NC) outputs. Also, a number of NO and/or NC auxiliary switches can be provided that follow the state of the power contactor outputs.
Main power conductors can enter a power distribution panel through a power contactor, which is typically employed to open and close, thereby controlling power to the panel. Downstream of the power contactor in the panel is a circuit for sensing current. In a three-phase power panel, for example, downstream current transformers are employed for sensing the current, and upstream circuit breakers are employed for providing overcurrent, phase imbalance and/or ground fault protection.
There is room for improvement in power contactors.
There is also room for improvement in systems including power contactors.